This invention relates to a method and apparatus for plotting graphics such as arrows and grids on a display device such as a cathode ray tube (CRT) screen.
In certain user-type machines such as a cash dispensing machine, it is frequently necessary to provide an associated display device on which "lead-through" instructions are displayed to instruct a user of the machine as to how to operate the machine. Certain graphics such as grids and arrows, for example, are displayed on the display device so as facilitate the use of the machine, for example, an arrow may point to a location where cash requested from the machine will be dispensed. Frequently, the display device utilized is a CRT screen.
A typical cash dispensing machine generally has a microprocessor included therein to perform many routine functions associated with the machine; however, the machine and several others like it are generally coupled to and controlled by a host controller via transmission lines. In the past, some of the graphics to be formed on the display device of a machine were sent from the host controller, requiring both an extensive memory in the host controller and an extensive or long transmission time in sending the data for the graphics to the display device of a dispensing machine.